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G. A. HAMILTON.

DYNAMO ELECTRIC MACHINE.

- Patented June 9, 1885.

INVENTOR Geoiye JZ .flamb'llon,

By his .v-Z/fmvzey N PETERS. Prawn-Lithographer, Washington. D. C,

UNITED STATES PATENT rErcE.

GEORGE A. HAMILTON, OF NEW YORK, N. Y., ASSIGNOR TO THE \VESTEBN UNIONTELEGRAPH COMPANY, OF SAME PLACE.

DYNAMO-ELECT'RIC MACl-llNE.

SPECIFICATION forming part of Letters Patent No. 319,578, dated .l'une9, 1885.

Application filed December 21, 1882.

.To all whom it may concern.-

Be it known that I, GEORGE A. HAMILTON, of the city, county, and Stateof New York, and a citizen of the United States, have made a new anduseful Improvement in Dynamo- Machines for Electric Telegraphy, of whichthe following is a specification.

This invention is particularly designed to enable a singledynamo-machine armature to IO feed many independent telegraph-lines eachof a different resistance from the others, and to therefore enable theprocurement of currents of a strength proportionate to the resistance ofthe lines to be fed. I am also en- 1 5 abled to procure from the samemachine different strengths of current of either polarity. To the end ofprocuring many different strengths of current from a singledynamo-machine I employ an armature having a series of coils, the

beginning and terminal ends of adjoining ones being respectivelyconnected together, and a series of insulated commutator-strips. Thereare thus as many commutator-strips as there are coil-sections upon thearmature, and the coil-seetions are connected together in an unbrokenmetallic circuit. In diametrically-opposite positions, in respect to theaxis of the armature, are two field-magnets, respectively of oppositepolarity.

Instead of employing two main or primary commutator-brushes, forming apart of the entire machinecircuit, adjusted to be in immediateconnection with those armature-coils which are in a neutral position, orin a plane nearly at right angles to the plane joining the poles of thefie1d-magnets,I employ only one such main or primary brush,which isimmediately connected to earth through a low resistance. In addition tothe single main brush .I employ as many other secondary or line brushesas different strengths of current are required, and these secondary orline brushes are given different circumferential positions of contactaround the commutator. From a line-brush in one position of adjustmentonly a weak current may be obtained, while, from one in a differentposition, any intermediate strength of current up to the maximum thatthe machine is capable of developing can be obtained. I will nowdescribe my inven- (N0 model.)

tion by reference to the accompanying drawings.

Figure 1 is a perspective view of an arma ture, such as may be employedin carrying out my invention. Fig. 2 is a diagram of a 5 commutator andarmature coil-sections, and a series of comnmtator-brushes for procuringcurrents of different strengths, though of the same polarity. Fig. 3represents an arrangement by means of which different strengths ofcurrent may be procured of either polarity.

In Fig. 2, C is a commutator having a cylindrical series of insulatedmetallic strips 1 2 3, &c., to which are attached metallic bars a b c,&c. To each of said bars a b c, &c., are attached the terminatingextremity of one armaturecoil and the beginning extremity of asucceeding one. Thus the beginning extremity of an armature-coil isattached by wire 20 to bar a, while the terminating extremity of thesame coil is attached by wire 21 to bar I). In the same mannerextremities of the second armature-coil, 22 23, are attached to bars I)c. The extremities of the third ar- 7 5 mature-coil, 24c 25, areattached to the bars 0 d. In like manner all of the armature-coils areconnected together in a closed metallic circuit, while at those pointsat which they are connected together a loop-connection is re- Sospectively formed with the insulated metallic strips of the commutator.N and S are poles of the field-magnets set in diametrically-oppositepositions in respect to the axis of the armature. Each coil of thearmature when ro- S 5 tated in the direction of the arrow will have acurrent of one polarity induced therein in one-half of its rotation, andof an opposite polarity in its other half rotation. Taking coil 20 21,after passing line A B, a current will be established in the directionindicated by the arrows, and the currents generated in these coils willgrow stronger as the coil is rotated toward the pole of the field-magnetN, and will gradually diminish until it again reaches 5 the neutral lineA I when the polarity of current generated in said coil will bereversed, and will, in turn, increase to a maximum as it passes the poleS, when it will again diminish to zero upon returning to said neutralline.

When the coil 20 21 is in position of rotation shown in the drawings,only a weak current will be generated therein. In the coil 22 23 astronger current will at the same time be developed, while the currentof coil 24 25 will be still stronger. The several currents of Va riablestrength generated by the different coils, according to their positionof rotation, are superposed, and conspire together to form a commoncurrent; and those armature coils, as shown in the drawings, whose commutator-sections are above the neutral line A B and those whose sectionsare below said line generate currents in the same manner as twobatteries connected together in multiple are; and, as is well known, acurrent is generated in coils connected to commutator-strips above theneutral line, running in one direction, while in the coils connected tostrips below said line a current is generated flowing in the oppositedirection.

If a circuit were established from brush X to earth, and thence throughthe armature-coil from bar a, a maximum current would be derived from abrush making contact with that commutator section diametrically oppositeto section 1. A current, however, of much less and any desired strengthcan be obtained by placing a brush in any required positionas, forinstance, brush Y in contact with the commutatorsection 4. In this casethe current furnished line L will be due to the electro-motive force setup in coils 20 21, 22 23, and 2a 25. In like manner, to procure a stillstronger current line L may be attached to a brush, Z, placed in contactwith commutatorsection 8, and in this case electro-motive force due toseven coils of the armature is employed. In fact, onehalf as manydifferent strengths of current may be procured as there are commutatorsections or armature -coils for the machine.

As shown in Fig. 2, there are sixteen commutatorsections and sixteenarmature-coils; and, having the brush X in contact with section 1, asmany different strengths of current may be obtained as there arecommutator-sections upon each side of the neutral line A I3. Thus inthis instance eight different strengths of current may be procured. Ifthere is practically no resistance between brush X and the earth, acurrent derived from any brushas Y, Z, or "W-will be that produced bythe electro-motive force of those coils connected to thosecommutator-strips between the respective metallic contact-bars a and d,a and h, and a and Z. It is to be observed, however, if the resistancebetween brush X and the earth E were equal to the resistance, forinstance, of line L, there would be a point of zero potential in thosearmaturecoils between bars a and h, and that therefore if line L werejoined by its brush Y to the armature-coils at such point of zeropotential no current would be set up in line L; and from the fact that aresistance may be inserted between brush X and earth E, and that a pointof zero potential in the coils of the armature may be thereby produced,it is obvious that the current produced upon line L may be varied instrength not only by shifting brush Y from one commutator-section toanother, but by increasing or decreasing the resistance between brush Xand earth E.

In practice, the neutral line A B is not at right angles to the linejoining the field-poles, though for convenience of illustration I haveshown the two lines as being at right angles.

Fig. 3 represents a commutator and electrical connections joining thestrips of said commutator and coils of the armature, substantially asshown in Fig. 2, having two brushes, X and Y, in contact with theneutral commutator'sections 1 and 9. By this means it is obvious thatnot only-can currents of different strength be derived from secondarybrushes differently positioned, but that currents of either polarity maybe obtained. For example, if the resistance of wires w w is equal, acurrent will be established in line L toward the commutator, asindicated by the arrow, while in line L a current will be generatedflowing from the commutator, as indicated by arrow.

Currents will be produced which flow toward the commutator in thoselines whose brushes are in contact with commutator-sections at the leftof the line joining the iieldpoles of the machine, while currents of anopposite polarity will be set up in all those lines whose brushes are incontact with those commutator-sections at the right of said line. Thecurrent established in line L is a resultant of a current generated bythose coils attached to commutator-sections 1 2 3 4- and those coilsattached to commutator-sections 4: 5 6 7 8 9. The coils of the armatureattached to sections 1 2 3 4c tend to produce a current in line L whosedirection is opposite to that of the arrow of line L, while thosearmature-coils attached to sections a, 5, 6, 7, 8, and 9 set up acurrent whose direction is indicated by the arrow. A current thereforeflowing in line L is less than that which would otherwise be produced bythose coils connected to commutator-seetions 4 5 6 7 8 9. In like mannera current set up in line is the difference between the current generatedby those coils of the armature attached to sections 1 2 3 at 5 6 7 andthose coils attached to the commutator-sections 7 S 9.

Instead of employing an armature whose coils are wound entirely upon itsperiphery and across its ends, I may employ the ordinary Grammearmature; or, in fact, any other form where the coils are all connectedtogether, and which at their junctions are connected, re spectively,with a series of commutatorstrips.

What I claim, and desire to secure by Letters Patent, is

1. As a means for procuring from one dynamo-machine several strengths ofcurrent, the combination of an armature whose coils are electricallyconnected together and to a series ofco1n1nutator-strips,acommutator-brush connected to earth by a conductor of low resistance,and a series of auxiliary brushes situated in different circumferentialpositions about the commutator, to which independent conductors arerespectively connected, and upon each of which conductors a differentpotential of current may be obtained.

2. The combination of a series of armaturecoils which are electricallyconnected together and to a series of commutator-strips substantially asdescribed, two field-magnets respect ively in diametricallyoppositepositions about the armature-axis, a commutator-brush X, connected bylow resistance to earth, and a series of main-line commutator-brushes,Y, Z, and W, to which are connected lines L L L.

